VIEWPOINT: GLOBAL WARMING NATURAL, MAY END WITHIN 20 YEARS

COLUMBUS, Ohio -- Global warming is a natural geological process
that could begin to reverse itself within 10 to 20 years, predicts
an Ohio State University researcher.

Robert Essenhigh

The researcher suggests that atmospheric carbon dioxide
-- often thought of as a key "greenhouse gas" -- is
not the cause of global warming. The opposite is most likely
to be true, according to Robert
Essenhigh, E.G. Bailey Professor of Energy Conservation in
Ohio State's Department
of Mechanical Engineering. It is the rising global temperatures
that are naturally increasing the levels of carbon dioxide, not
the other way around, he says.

"According to Essenhigh's estimations, Earth
may reach a peak in the current temperature profile within the
next 10 to 20 years, and then it could begin to cool into a new
ice age."

Many people blame global warming on carbon dioxide sent
into the atmosphere from burning fossil fuels in man-made devices
such as automobiles and power plants. Essenhigh believes these
people fail to account for the much greater amount of carbon
dioxide that enters -- and leaves -- the atmosphere as part of
the natural cycle of water exchange from, and back into, the
sea and vegetation.

"Many scientists who have tried to mathematically determine
the relationship between carbon dioxide and global temperature
would appear to have vastly underestimated the significance of
water in the atmosphere as a radiation-absorbing gas," Essenhigh
argues. "If you ignore the water, you're going to get the
wrong answer."

How could so many scientists miss out on this critical bit
of information, as Essenhigh believes? He said a National
Academy of Sciences report on carbon dioxide levels that
was published in 1977 omitted information about water as a gas
and identified it only as vapor, which means condensed water
or cloud, which is at a much lower concentration in the atmosphere;
and most subsequent investigations into this area evidently have
built upon the pattern of that report.

For his hypothesis, Essenhigh examined data from various other
sources, including measurements of ocean evaporation rates, man-made
sources of carbon dioxide, and global temperature data for the
last one million years.

Compared to man-made sources' emission of about 5 to 6 billion
tons per year, the natural sources would then account for more
than 95 percent of all atmospheric carbon dioxide, Essenhigh
said.

"At 6 billion tons, humans are then responsible for a
comparatively small amount - less than 5 percent - of atmospheric
carbon dioxide," he said. "And if nature is the source
of the rest of the carbon dioxide, then it is difficult to see
that man-made carbon dioxide can be driving the rising temperatures.
In fact, I don't believe it does."

Some scientists believe that the human contribution to carbon
dioxide in the atmosphere, however small, is of a critical amount
that could nonetheless upset Earth's environmental balance. But
Essenhigh feels that, mathematically, that hypothesis hasn't
been adequately substantiated.

Here's how Essenhigh sees the global temperature system working:
As temperatures rise, the carbon dioxide equilibrium in the water
changes, and this releases more carbon dioxide into the atmosphere.
According to this scenario, atmospheric carbon dioxide is then
an indicator of rising temperatures -- not the driving force
behind it.

Essenhigh attributes the current reported rise in global temperatures
to a natural cycle of warming and cooling.

He examined data that Cambridge
University geologists Nicholas Shackleton and Neil Opdyke
reported in the journal Quaternary
Research in 1973, which found that global temperatures
have been oscillating steadily, with an average rising gradually,
over the last one million years -- long before human industry
began to release carbon dioxide into the atmosphere. Opdyke is
now at the University of Florida.

According to Shackleton and Opdyke's data, average global
temperatures have risen less than one degree in the last million
years, though the amplitude of the periodic oscillation has now
risen in that time from about 5 degrees to about 10 degrees,
with a period of about 100,000 years.

"Today, we are simply near a peak in the current cycle
that started about 25,000 years ago," Essenhigh explained.

As to why highs and lows follow a 100,000 year cycle, the
explanation Essenhigh uses is that the Arctic Ocean acts as a
giant temperature regulator, an idea known as the "Arctic
Ocean Model." This model first appeared over 30 years ago
and is well presented in the 1974 book Weather Machine: How our
weather works and why it is changing, by Nigel Calder, a former
editor of New Scientist
magazine.

According to this model, when the Arctic Ocean is frozen over,
as it is today, Essenhigh said, it prevents evaporation of water
that would otherwise escape to the atmosphere and then return
as snow. When there is less snow to replenish the Arctic ice
cap, the cap may start to shrink. That could be the cause behind
the retreat of the Arctic ice cap that scientists are documenting
today, Essenhigh said.

As the ice cap melts, the earth warms, until the Arctic Ocean
opens again. Once enough water is available by evaporation from
the ocean into the atmosphere, snows can begin to replenish the
ice cap. At that point, the Arctic ice begins to expand, the
global temperature can then start to reverse, and the earth can
start re-entry to a new ice age.

According to Essenhigh's estimations, Earth may reach a peak
in the current temperature profile within the next 10 to 20 years,
and then it could begin to cool into a new ice age.

Essenhigh knows that his scientific opinion is a minority
one. As far as he knows, he's the only person who's linked global
warming and carbon dioxide in this particular way. But he maintains
his evaluations represent an improvement on those of the majority
opinion, because they are logically rigorous and includes water
vapor as a far more significant factor than in other studies.

"If there are flaws in these propositions, I'm listening,"
he wrote in his Chemical Innovation paper. "But if
there are objections, let's have them with the numbers."